First speeding traffic lights!: Motoring Motoring Discussion forum

Motoring Discussion > First speeding traffic lights!	Miscellaneous
Thread Author: Falkirk Bairn	Replies: 20

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Tue 17 Mar 15 19:46

First speeding traffic lights! - Falkirk Bairn

Speed - the lights turn red

Common in Spain I believe, but 1st time in Scotland

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Tue 17 Mar 15 21:00

First speeding traffic lights! - R.P.

For some reason, thirty years ago mind you, I was told that if you hit traffic lights in Cardiff at the right speed - they would be green all the way through.

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Tue 17 Mar 15 21:11

First speeding traffic lights! - WillDeBeest

Used to be the case on the A4 through Slough, according to my mum who worked and drove there in 1960 or so. Certainly isn't today.

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Tue 17 Mar 15 22:01

First speeding traffic lights! - No FM2R

Certainly was. I used to come along the A4 from Maidenhead when I worked on the Farnham Road. Get it right and you could get all tge way along to the pub ( The Three Tuns maybe?).

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Tue 17 Mar 15 22:17

First speeding traffic lights! - swiss tony

>> Certainly was. I used to come along the A4 from Maidenhead when I worked on
>> the Farnham Road. Get it right and you could get all tge way along to
>> the pub ( The Three Tuns maybe?).
>>
Correct.
28 mph, or 56mph. never managed a constant 84....

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Wed 18 Mar 15 00:28

First speeding traffic lights! - No FM2R

>>never managed a constant 84....

Hah! At that time I never owned a car which could do a constant 84 whatever the road conditions.

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Tue 17 Mar 15 22:03

First speeding traffic lights! - Stuartli

>>For some reason, thirty years ago mind you, I was told that if you hit traffic lights in Cardiff at the right speed - they would be green all the way through.>>

Used to be the same on some roads around the Liverpool and Bootle Docks area I was once told by a traffic police officer friend.

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Tue 17 Mar 15 22:50

First speeding traffic lights! - Alastairw

Absolutely I used call it riding the green wave along Childwall Valley Road. Very satisfying as each light turns green just as you reach it.

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Wed 18 Mar 15 01:27

First speeding traffic lights! - Armel Coussine

I remember those phased traffic lights through Slough. Try as I might, I never managed to get through all of them without being held up. Couldn't go slowly enough. Of course I was younger in those days. It would be a doddle now.

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Wed 18 Mar 15 06:51

First speeding traffic lights! - swiss tony

>> I remember those phased traffic lights through Slough. Try as I might, I never managed
>> to get through all of them without being held up. Couldn't go slowly enough. Of
>> course I was younger in those days. It would be a doddle now.
>>

Like I said above AC, they were set at 28mph.
Or any multiple thereof..... ;-)

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Wed 18 Mar 15 06:57

First speeding traffic lights! - swiss tony

Just remembered something a mate told me about working in Slough...

He worked at BICERI, and was testing the K series engine in a Metro.
seems he could hit 120 from a standing start between the lights in Buckingham Ave.
The engine was somewhat detuned for production!

Last edited by: swiss tony on Wed 18 Mar 15 at 06:58

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Wed 18 Mar 15 07:20

First speeding traffic lights! - WillDeBeest

Now I'm lost. Suppose light A and light B are half a mile apart and phased to be green for 30 seconds and red for 30 (counting the amber time as red.) A car travelling at 30mph will reach B one minute later, at the same point in the cycle as it was when it left A, so if the cycles are spaced correctly B will also be green. But if the car travels at 60mph, it will arrive at B in 30 seconds, when B will at the opposite point in its cycle and will be red.

I suppose if the lights were further apart, or the cycles shorter, it would be possible to get to the next one in one cycle rather than two, but even so 'any multiple' can't be true; no more than 30 x number of cycles between lights at 30.

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Wed 18 Mar 15 19:25

First speeding traffic lights! - BobbyG

I remember seeing lights like these in France but the lights were positioned on the main road going through a village.
However they weren't positioned at a junction, just on the main street.

Therefore, if you are willing to speed, then would you not just go through the red light?

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Wed 18 Mar 15 19:40

First speeding traffic lights! - Cockle

>>
>> Therefore, if you are willing to speed, then would you not just go through the
>> red light?
>>

Red light camera attached?

If you go through the red then, QED, you are a habitual law breaker and deserve the fine.

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Thu 19 Mar 15 08:36

First speeding traffic lights! - martin aston

I have encountered these in Spain. While great in theory the problem with them was that they defaulted to red ( at least in the area I was visiting). So you approach a red light and if you are at or below the speed limit the light will change to green before you cross the painted line at the light. The problem with the one in the local town was that it changed to green just a few meters before you hit the line. Locals are used to it and just bomb through but if you ease off to be sure you don't jump the light you get a local on your tail flashing. You might argue you get used to it but I can't help thinking it's not a good idea to confuse our driving instincts with some lights where your automatic reaction is to stop (ie normal lights) and another set where the aim, and therefore the instinct you develop, is to keep going at speed in the expectation it will change. A default of green would be better as in both cases red means stop now.

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Thu 19 Mar 15 09:14

First speeding traffic lights! - BiggerBadderDave

There are two sets close to a school in my village. If you exceed 50 kph the lights turn to red - fine except they've placed the sensor too close to the light - the offender has long gone and it's the second in line driver who gets the red light. A camera might sort out the problem.

There's a long, fast stretch of dual carriageway from our village heading into the centre. In the early hours, all lights are switched from regular phase to rapid-sequence phase. They go red every 5 or 10 seconds so you have to slow down, you can't race through like an idiot even if nobody is around. You always get a red on approach, however you try and time it. And as above - no cameras - so I've seen drivers ignoring the lights and just zooming through (including me on early airport runs) but it does slow down the majority.

Through the night a lot of the lights in Warsaw are switched off and simply flash amber - the 50 kph junctions, not the dual carriageways. It's actually a good idea - none of that sitting at red lights for no reason when the streets are desolate and there's no other traffic. It's a kind of 'drive straight through all lights, but keep a look out for cars using your junction' policy. I like it. It seems to work well.

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Thu 19 Mar 15 11:27

First speeding traffic lights! - Cliff Pope

I can see how this system can work if you are only considering the traffic on the main route.
But changing the lights to green to fast-track one driver surely means that another driver, on a side road, suddenly finds his green light turned to red?

It can't ensure that all lights are green for everyone in all directions.

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Thu 19 Mar 15 11:57

First speeding traffic lights! - Manatee

There's a narrow, blind humpback type bridge near here controlled by traffic lights.

The lights at both ends default to red. It stays like that until somebody arrives, then goes green for them as they approach. Good system most of the time because you never have to wait unless there is actually somebody coming the other way. If you are going too fast you have to stop of course, but slow enough to give it time to react anf you're OK.

Maybe that's what's happening with BBDs Polish ones.

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Thu 19 Mar 15 12:36

First speeding traffic lights! - BiggerBadderDave

Ah, you see there's another thing - the side-streets always get a green light (a tiny little green arrow next to the red light) for a right-turn (or to turn left in the UK). So you can join the main road without waiting at red lights and there's 100m to filter in. To turn left and cross the carriage way first (or to turn right in the UK), you have to wait for the lights to change. You don't want to be t-boned.

This is the case in almost every junction here (and across central Europe probably), you can turn right almost any time. You just have to be careful with pedestrians crossing - they have priority, you wait for them. And they should do that in the UK too, you should be able to turn left and join the crossing traffic, just wait for a gap and zip out. This happened in one cross-junction in Cheadle, South Manchester 25 years ago and they've stopped it. Numpties.

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Thu 19 Mar 15 12:38

First speeding traffic lights! - Bromptonaut

>> There's a narrow, blind humpback type bridge near here controlled by traffic lights.
>>
>> The lights at both ends default to red.

You also need to creep all the way to the stop line in order to be detected. On more than one occasion I've waited ages and then had to tap on somebody's window to persuade the to edge forward the last few metres.

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Thu 19 Mar 15 22:09

First speeding traffic lights! - busbee

Slow approach to traffic lights

"You have to creep towards a traffic light to be detected" " And often you don't get detected!"

If the vehicle detector is a radar on top of the light, as opposed to one using a buried loop, I am not at all surprised. Your approach speed is just too low. (But OK for a loop)

Why? Because the radar (more appropriately called a microwave vehicle detector) is designed to be less sensitive to low speeds, in order to reduce interference caused by pedestrian movement.

About lights in general, for a narrow bridge or tunnel, it helps if the lights are turned to all-red with no traffic demand (a demand is a detection of an approaching vehicle) as that allows the fastest green response. Once all red time exceeds what is needed for junction clearance, the lights are able to instantly start to change down through amber to green in response to a demand from any direction.

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